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Hearing Problems in Pediatrics A Discussion of Hearing Problems in Children Function of the Normal Ear The ear is divided into three parts: an external ear, a middle ear and an inner ear. Each part performs an important function in the process of hearing. The external ear consists of an auricle and ear canal. These structures gather the sound and direct it toward the eardrum membrane. The middle ear chamber lies between the external and inner ear. This chamber is connected to the back of the throat by the Eustachian tube which serves as a pressure equalizing valve. The middle ear consists of an eardrum membrane and three small ear bones (ossicles): malleus (hammer), incus (anvil) and stapes (stirrup). These structures transmit sound vibrations to the inner ear. In so doing they act as a transformer, converting sound vibrations in the external ear canal into fluid waves in the inner ear. The inner ear chamber contains the microscopic hearing nerve endings bathed in fluid. Fluid waves stimulate the delicate nerve endings which in turn transmit sound energy to the brain where it is interpreted. Types of Hearing Impairment The external and middle ear conduct and transform sound; the inner ear receives it. When there is some difficulty in the external or middle ear a conductive hearing impairment occurs. When the trouble lies in the inner ear, a sensori-neural or nerve hearing impairment is the result. Difficulty in both the middle and inner ear results in a mixed impairment. Conductive Impairment A conductive impairment may result from blockage of the external ear canal, from a perforation (hole) in the eardrum membrane, from middle ear infection, from fluid accumulation due to blockage of the Eustachian tube, or from a congenital defect or disease of any of the three middle ear bones. This type of impairment is usually correctable through surgery. Fortunately the child with a conductive hearing impairment will never go deaf. He will always be able to hear, either through ear surgery or by use of a properly fitted hearing aid. Sensori-Neural Impairment Sensori-neural impairment is the term used to describe hearing impairments which result from disturbances or defects in the inner ear and nerve transmission. These impairments may be congenital (present at birth), hereditary, or developmental, or a combination of these. Virus Diseases German measles contracted by a mother during the first three months of pregnancy may interfere with inner ear development in the fetus. Occasionally other virus diseases are at fault. The viruses of measles and mumps may cause a sensori-neual impairment after birth but this happens infrequently. Problems at Birth Jaundice occurring at or shortly after birth is capable of damaging the inner ear. This is most often due to Rh incompatibility between the mother’s and the child’s blood. Fortunately this is uncommon. A vaccine has been developed which may prevent this problem in the future. A very difficult or complicated labor may result in inner ear damage at times. Hereditary Impairment Hereditary sensori-neural hearing impairment may be present at birth, or may develop later in life. Even though there may be no hearing impairment in the parents, careful questioning often reveals some more distant relative with a similar problem. Treatment There is no known medical treatment that will restore hearing in sensori-neural impairments. We must rely on rehabilitation through use of a hearing aid and special training. Fortunately only one in a hundred children with this type of impairment will show progression of the impairment over the course of years. In cases of total deafness, a cochlear implant operation may be an option for the patient. Cochlear implantation is done at specialized centers with a team of surgeons, audiologist, and speech pathologists. Hearing Impairment in One Ear A hearing impairment that is confined to one ear deprives a person of the ability to distinguish the direction of sound. He will also have difficulty hearing from the involved side in a noisy background. These are minor problems to a young child. When this impairment is conductive, surgery is usually possible to restore the hearing, giving a better auditory balance when the loss becomes a problem, usually in the teens. When the impairment is sesorineural it is often possible when the child grows older to restore some of this balance through use of a special hearing aid (CROS aid). Rehabilitative Measure A complete otologic examination by a competent ear specialist is necessary to determine what type of hearing impairment is present, its probable cause and its treatment. At times it may be necessary to obtain x-rays, a balance test or other laboratory tests to make this decision. The treatment of choice may be remedial, preventive, medical, surgical or a combination of these. Each child with impaired hearing should have the benefit of adequate auditory rehabilitation. A well-rounded program of rehabilitation for a child with a hearing deficiency may include speech reading, auditory training, speech conservation and improvement and instruction in the use of a hearing aid. All aspects of the program do not necessarily apply to each individual with an impairment but each can be helpful through some of these methods. The possibility of rehabilitative assistance should not be overlooked; the benefits can be very great. Hearing Aid Evaluation Evaluation of the hearing in a young child may require several visits with the audiologist. It is import to arrive at an accurate measurement of both the type and degree of impairment in order to select the proper aid. An aid that is too powerful for a young child may irritate his ears and cause him to reject it. On the other hand, if the aid is not strong enough, a child may receive little or no benefit from it and object to wearing it. It can be difficult to encourage children in regular classrooms to wear hearing aids, especially adolescents. However, the learning experience is vital to help children reach their maximum potential in adulthood. For these reasons, it is important in adulthood. For these reasons, it is important that children wear their hearing aids in school. Speech Reading Speech reading is very important whatever the type or degree of impairment. This skill enables a person with impaired hearing to understand conversation by attentively observing the speaker. All of us, whether we have a hearing loss or not, employ the sense of sight as well as the sense of hearing in ordinary conversation. We find it easier to comprehend if we can watch the speaker’s facial expressions, lip movements and gestures. Just as the visually handicapped learns to use his sense of hearing to compensate for his impaired sight, so the person with defective hearing must learn to use his eyes to assist him in hearing. A study of the fundamentals of lip-reading or of speech reading, as it is called, will make communication less of an effort and therefore more pleasant for both the speaker and the listener. Speech reading has its limitations. For example, when the distance between the speakers is great or when the distance between the speakers is great or when there is faulty lighting or defective vision, one may not always be able to see the speaker’s lips clearly enough to speech read adequately. Some persons do not open their mouths very far when they speak and in consequence their lip movements are very limited. Others have beards, hold their hands over their mouths or smoke as they talk, making speech reading difficult if not impossible. Because most sensori-neural hearing impairments involve primarily the higher frequencies, the child must therefore rely on these visual clues to understand what is being said. It is the high-frequencies that include consonant sounds or those sounds made with the lips, teeth or tongue. For instance, the words “fit,” “sit,” and “bit” may sound the same but will look differently when pronounced by the speaker. It is imperative that children receive preferential seating in the classroom (front and center) so as to gain the most from visual cues. The teacher must always be informed when there is a hearing loss present, either temporary or permanent. This way, she can plan academic programs to suit the child as well as keep up with progress more effectively. Profound Sensori-Neural Hearing Impairment If you child’s hearing level is greater than 70dB he will not, in all likelihood, be able to attend classes with normal hearing children, at least in the beginning. It will be difficult for him, but with help of a hearing aid, training and speech reading and attention to speech correction, he may be able to progress through schools for the hearing handicap to normal schools, even to college, to take his place in a society with normal hearing people. For those children who are not able to achieve understanding for speech, special schools are available to train them in the manual form of communication (finger spelling) and to train them in specific trades. The type of school a child attends depends upon his progression in communication. The Future Cochlear implantation can be used in your (pre-lingual) children who have not yet learned to speak, as well as, older children who have lost their hearing after obtaining the ability to speak (post-lingual). Generally, post-lingual children obtain the best result in terms of communication. Pre-lingual children who undergo cochlear implantation do not achieve “normal” hearing the way the non-hearing impaired patient understands it. However, even pre-lingual deaf children can achieve the ability to talk on the phone and hear waving signals, such as car horns, door bells, etc. Regardless, cochlear implantation requires a lot of post-generative rehabilitation / training and should not be considered an option lightly.